Mangrove Evolution in Mayotte Island, Indian Ocean: A 60-year Synopsis Based on Aerial Photographs

The Island of Mayotte, in the Indian Ocean, is characterized by a highly diversified shoreline comprising numerous mangrove zones set within a vast coral reef and lagoon complex. An analysis of aerial photographs covering the period from 1950 to 2011 shows marked variability in the evolution of these mangroves and clear spatial differences in the dynamics of these communities over the 60-year period of analysis. The northern part of the island shows stability or a slight increase in mangrove area whereas the southern and western shores of the island have been characterized by a clear regression in mangroves. The total surface area of mangroves on Mayotte (7.03 km(2) in 2011) has diminished overall by about 5 %, a relatively moderate figure relative to the world context of increasing diminution of mangrove area. The pattern of evolution of mangroves in Mayotte is explained jointly by development pressures on the coast and spatial variability in mangrove recovery determined by hydrological conditions and exposure to waves on this reef-fringed island. Mayotte Island acquired the status of a French administrative department in 2011 subject to both French and European Community legislation on the environment. In consequence, mangroves are now much better protected from future urbanization.